Aeronáutica Civil de Colombia (Aerocivil) has contracted a consortium made up of Ineco and Colombian engineering firm Integral to carry out research for the implementation of Apron Management Services (AMS) at the Eldorado International Airport in Bogotá. The AMS service is operated from the airport control tower, and its function is to manage aircraft traffic on the ground.

The research includes a detailed study of all the requirements for the optimum performance of the AMS, including an analysis of Colombian aeronautical regulations, safety requirements, professional profiles, equipment, installations, radio aids, software, hardware, communications and procedures.

The company, which implemented and provided this service from 2011 to 2017 at Barajas airport, will define the strategies and action plan for Aerocivil to determine the best technical-economic alternative to be implemented in 2021.

“To create a unique symbol for each place”

Bruce Fairbanks, founder of Fairbanks Arquitectos, has accumulated extensive experience in the design of airport buildings since 1996 when he won the tender for the construction of the Madrid-Barajas control tower.

Presently in the world of airports there is a trend to promote the control tower as a symbol, an image that represents the airport and a reference point for the arrival in, and departure from the city where it is located. This trend has created increased interest in architectural execution in the design of control towers in addition to their functional requirements. It is precisely the individuality of these requirements that significantly affects the type of building, such that throughout history there are various examples of “types” of tower designs, which, once designed, were repeated in various airports: one notable case is the leoh Ming Pei control tower. It was designed between 1962 and 1965 with the objective implementation in 70 airports, although in the end 16 were built. The concept of locating in upper levels strictly that which was necessary was developed, putting the maximum amount of functions in the base building, which was adapted to the specific characteristics of each location. As such, the tower could be prefabricated and repeated with standardised equipment, giving the airport network an image of safety since a controller could work in any location without having to adapt. The tower was designed with 5 standardised heights (18-46 m) in accordance with visibility requirements in each location. The control tower’s cab is pentagonal so there are no parallel façades and so as to avoid reflections. In Spain, in the 1970s, Juan Montero Romero, an aeronautical engineer, built a tower, which was repeated in several cities: Málaga, Alicante, Valencia, etc.

To create a landmark, the architect must find within the functionality the characteristics that distinguish one tower from others

Converting control towers into airport landmarks and reference points for cities is a challenge in the work of an architect: creating a symbol, always unique for each location, which meets all of the requirements for the optimal functioning of the tower. The location, the height of the control room, its form and the layout of its structural elements are some of the first elements to define. Control towers typically have a base building and a shaft that supports the upper floors, which are designed to adapt to the control operations. Given the form, with an upper part and a lower part and the height of the type of building, in my opinion it is essential to incorporate the construction process into the design of the tower, and this is what I have done in those which I have designed. This design comes from an analysis of the functional aspects, the programme and the location. To create a landmark, the architect must find within the functionality the characteristics that can distinguish one tower from others and strengthen them to create a unique tower with its own character in each case.

Analysis of four cases

The following examples of control towers show diferente conceptual approaches to design this building type and the elements that diversify its design.

1962. Dulles airport, Washington DC
Eero Saarinen

The Dulles tower has all of the equipment rooms at a height, elegantly assembled by Saarinen with two juxtaposed bodies. The form of the tower is integrated with that of the terminal building, also designed by the same architect.

1992. JFK airport, Nueva York
Pei Cobb Freed & Partners

The upper part of the JFK tower, 97.5 metres in height, contains only the aerodrome control cab and half way up the shaft there is the platform control room, which takes the same form as the upper levels.

1997. Adolfo Suárez Madrid-Barajas airport
Bruce Fairbanks

The Adolfo Suárez Madrid-Barajas control tower had the specific feature of a 400 m² equipment room located at a height. To resolve the transition between the shaft of the tower and the projection, an inverted half sphere was adopted, with a floor for air conditioning equipment being inserted in the support. The octagonal shape defined for the
cab is extended throughout the top of the building, the structural design of a central column and 8 perimeter columns is repeated on all levels.

Another particular feature of the tower is the construction system designed as an integral part of the design. The shaft is built with prefabricated segments assembled in spirals, which, on the inside, contain the service ducts and circumscribe the emergency stairway. The upper floors were built with a metallic structure on the floor and subsequently hoisted onto the shaft. The system allowed the tower to be built in nine months, without using scaffolding.

2004. Barcelona-El Prat airport
Bruce Fairbanks

The functional requirements were similar to those of Barajas, with the exception that a large part of the equipment is located in the base building. The resistant structure is defined independently from the functional elements of the shaft, which was developed as a representative design element. An eight-pointed hyperbola generated from the octagonal shape of the cab holds the upper floors.

The hyperbola links the tower with Catalan Modernism and Antoni Gaudí, who used this form in many of his designs, including on the domes of the Sagrada Familia. The construction system is a representative part of his design. The assembly of the hyperbola, built with prefabricated concrete girders, was guided by a central aluminium structure designed to contain the elements of the shaft. The upper floors were built on land and hoisted into position, supported by the eight points of the hyperbola, consolidating the whole structure when it was under load.

“In the future, it will not be necessary to view operations”

Roberto Serrano has participated in more than 50 aeronautical projects, amongst them, the NET and SAT control towers of Madrid-Barajas airport and the new control tower of Eldorado airport (Bogotá).

Although the first control towers date back to the 1920s (in 1921, Croydon airport in London was the first in the world to introduce air traffic control), it was from the 1930s that they became commonplace, due to the fact that growing aircraft traffic made controlling and managing it necessary. At that time, in which technology was nothing like the current systems, the need to visually supervise aeronautical operations around the airport was met by placing the control room (cab) in an elevated and predominant position of the airport (control tower).

To date, the first steps in designing a control tower involve establishing its site and the height of the cab. Internationally, to meet the viewing requirements from the cab, the recommendations of the Federal Aviation Administration (FAA) are applied. The optimum height and location of a control tower is the result of weighing up many considerations. The view from the cab requires the air traffic controller to be able to distinguish the aircraft and vehicles that circulate in the manoeuvring area, as well as aircraft that fly over the airport, particularly in take-off and landing paths. The objective is to have the maximum visibility possible and avoid the sun, external light sources and reflections from adjacent buildings affecting the visibility of the controller.

Nowadays, technology allows a practically blind landing

With regard to the location, we must consider the potential effects of local weather: flood areas or areas susceptible to fog. Its compatibility with the potential future development of the airport must also be studied, thereby avoiding the need to relocate the tower before the end of its life cycle. Insofar as possible, the tower and its buildings should be located on the landside of the airport, thus avoiding access through the airfield and facilitating the entry of staff. Furthermore, the location should be such that it does not affect the quality of the signals of the airport’s radio navigation aids (ILS, VOR, DME, etc.), or communication systems. The minimum height required for the control tower can be obtained with the aid of the FAA visibility analysis tool, ATCTVAT (Airport Traffic Control Tower Visibility Analysis Tool), in accordance with the physical conditions of the airport.

Once the position and height has been determined, the infrastructure is designed, and generally includes a cab and an antenna field, which, located on the roof of the cab, normally has communications antennas, radio relays, and other electronic and lightening protection elements. Furthermore, there are areas for staff, equipment, power, air conditioning, etc.

In an era in which technology provides information to pilots to allow a practically blind landing, is it necessary to keep air traffic controllers in a high position so they can see these operations? In the future, air traffic control rooms will probably be in buildings that are more similar to those of offices or air traffic control centres than the current towers.

The future has already become reality

2015. Control tower of Örnsköldsvik airport, Sweden

Recently, Örnsköldsvik airport in Sweden replaced its control tower with high-tech cameras. Signals are sent to controllers stationed in Sunvsal airport, located around 150 kilometres away, from a 25-metre mast with 14 high-definition cameras. The high performance of these cameras eliminates blind spots, provides information in rain, fog or snow and, along with a whole series of weather sensors, microphones and other devices, it allows controllers to feel as if they were beside the runway. The Swedish Transport Agency approved remotely operated towers on 31 October 2014. Six months later, the first airplane landed in Örnsköldsvik airport using the remote tower services.

Four million passengers in 2016: this is the growth forecast for the Rafael Núñez airport in Cartagena de Indias according to SACSA, the concession company. Majority-owned by the Spanish company Aena Internacional, in 2011 SACSA embarked on a project to improve and expand airport facilities, both on ground and in the air, in order to adapt airport capacity to the growing demand. Ineco recently updated the airport’s Master Plan which plans for expansion work until 2020 and has also designed and coordinated construction work (see IT48). Five years ago, work began on passenger terminal building renovations and expansion; work then continued on the design and surveillance of work on the runway, aprons, the perimeter road and the new FBO terminal for general aviation services.

The increase in traffic at the airport is associated with the tourism and industrial activity in this city –located on the coastline of the Caribbean Sea–, whose characteristic, walled historic quarter has been a UNESCO World Heritage Site since 1984. The city stands out as a domestic holiday destination, and although the number of international arrivals has increased, the majority of the city’s air traffic is mainly domestic with connections to the capital, Bogotá, as well as to main cities such as Medellín and Cali. In terms of international flights, top destinations include southern Florida in the United States in addition to Chile, Venezuela and Spain.

In order to drive the tourism sector, the airport operator and local entities such as Corporturismo and the Cartagena City Council are committed to implementing additional long-distance routes both to North America –the city’s main source of outbound tourism– and to Europe –especially to Germany and Spain. Airlines are thus operating larger aircrafts, in turn requiring airports to provide greater capacity as well as increased safety and security –both operational and physical. Since all work must be carried out without interfering with airport operations, Ineco also conducted a study on the different stages of construction in order to minimise the effects as much as possible.

Greater passenger and aircraft capacity

Thus, the construction work that was carried out at Rafael Núñez airport met these requirements: the current terminal building which was expanded from 2011 to 2013 has grown from 10,491 m² to 19,370 m². Expansion of the international hall is currently under way. The runway in addition to the main and secondary (or ECO) aprons were repaved between 2013 and 2014 to repair damaged areas and to increase their load bearing capacity. The axis of the turnaround area was modified to make it easier for large aircrafts to move around, and signalling and traffic guidance equipment was also improved.

With regard to the runway, Ineco designed and coordinated the installation of an asphalt mix that had never before been used in Colombia: a discontinuous, BBTM-11 bituminous mixture (with additional fibres) in a 4-cm screed used on 1,740 metres of the runway’s 2,540 total metres. The asphalt not only improves friction conditions on the wearing surface, but it also facilitates drainage and prevents hydroplaning.

On both aprons, a P-401 bituminous hot mixture with a maximum aggregate size of ¾” was used with a BMIII modified asphalt, with varying thicknesses of 5 to 12 centimetres. The landing gear stop-way was also reinforced with 33-cm concrete slabs. Since there are fewer demands with regard to reinforcements on the perimeter road and pedestrian areas, a MDC-2 bituminous hot mixture with B60/70 asphalt was installed.

General aviation on the rise

In addition to the aforementioned interventions which are of vital importance in terms of aircraft safety, the increase in general aviation traffic was kept in mind. Private and military flights represent more than 90% of traffic at this airport, while the remaining percentage is represented by executive flights, school flights, etc. Although general aviation represents less than 1% of the total passengers who use this airport, it corresponds to 30% of airport operations and is expected to grow an average of 3.9% by 2020, totalling some 26,000 passengers and 14,000 operations.

Therefore, construction work was carried out on a new FBO general aviation terminal in 2014 (Fixed Base Operator, a company from the United States in this case), as agreed upon in the draft that had previously been drawn up by Ineco. The new terminal, located in the eastern part, boasts three different areas: airport authority, border control and entry/exit of passengers and baggage; a surveillance area that covers access areas both to and from air and ground, as well as security checkpoints; and a passenger waiting area.

The project included the construction of a new, stand-alone building with an electrical substation, a hydraulic pump room and a drinking water supply in addition to a handling office. Shared with the secondary apron, a new perimeter road was also constructed with direct access from Vía del Mar, the road that connects Cartagena de Indias with Barranquilla.

The growth forecast predicts that Rafael Núñez airport will see four million passengers in 2016

Ongoing work

Rescue and fire fighting services (RFFS) are fundamental elements when it comes to increasing an airport’s capacity. Aeronautics and airline regulations require that the capacity of these services must be rigorously determined by the size (total length and fuselage width) of the aircrafts that normally operate at the airport. Therefore, airports are categorised on a scale of 0 to 10; Rafael Núñez airport falls into category number 7, meaning that this airport would need a minimum of two fire-fighting vehicles, one fire chief and four firefighters.

Nonetheless, the new facilities designed by Ineco provide for the possibility, also foreseen in the regulations, of increasing these resources if, with prior notification, the airport needed to occasionally accommodate aircrafts corresponding to higher categories. For this reason, airport sheds have space for four vehicles: three fire engines and one light-weight commanding vehicle.

Seeing as this airport operates 24 hours a day, the RFFS requires staff to cover three shifts; thus, the new building has the appropriate facilities for said staff to rest in addition to offices, warehouses, technical areas and a car park. In front of this building there will be a paved clear zone that will allow for aircrafts to transition to the military area. Additionally, there will be two water deposits each containing 30,000 litres of water supply for the fire engines, and said fire engines will also be provided with a new access road, thus facilitating their arrival to the runway in under three minutes. Ineco is overseeing the construction work and is also monitoring compliance with the Operational Safety Plan.

Another ongoing project coordinated and monitored by the company includes the enlargement of the runway safety strip; in some areas, this strip does not meet the required distance of 75 metres between the runway axis and the border of the airport. To meet this requirement, ground is being gained from the area of vegetation by reinforcing it with 5-metre long micropiles.